Update and calculate value through SQL Cursor

Question

I have two columns (TSD_BALANCEUNITS and TSD_UNITSINCERT). TSD_BALANCEUNITS has numeric values and TSD_UNITSINCERT has 0.00

By using cursor I want to update values of TSD_BALANCEUNITS to TSD_UNITSINCERT until the total sum of values updated in from TSD_BALANCEUNITS to TSD_UNITSINCERT is equal to 199.00

and the values of TSD_BALANCEUNITS which is being updated becomes 0.00 and moved to TSD_UNITSINCERT when total sum of moved values is equal to 199.00

Below is the script that I am using ...

        DECLARE @cnt INT = 0;
        DECLARE @TSD_BALANCEUNITS AS DECIMAL(25, 4)
        DECLARE @TSD_UNITSINCERT AS DECIMAL(25, 4)
        DECLARE @CHECKFLAG AS DECIMAL(25, 4)
        DECLARE LOCK_CERT_UNITS CURSOR LOCAL STATIC
        FOR

        SELECT TSD_BALANCEUNITS
            ,TSD_UNITSINCERT
        FROM IS_TRX_TRX_PROCESSED
        WHERE (TSD_ACCCODE = 8775)
            AND TSD_BALANCEUNITS > 0
        ORDER BY TSD_REALIZEDDATE ASC


        OPEN LOCK_CERT_UNITS

        FETCH NEXT
        FROM LOCK_CERT_UNITS
        INTO @TSD_BALANCEUNITS
            ,@TSD_UNITSINCERT

        WHILE @@FETCH_STATUS = 0 --AND @cnt < 199.00
        BEGIN
            SET @TSD_UNITSINCERT = @TSD_BALANCEUNITS
            SET @CHECKFLAG = + @TSD_BALANCEUNITS

            IF (SUM(@CHECKFLAG) <= 199.00)
            BEGIN
                UPDATE IS_TRX_TRX_PROCESSED
                SET TSD_UNITSINCERT = TSD_BALANCEUNITS
                WHERE (TSD_ACCCODE = 8775)
                    AND TSD_BALANCEUNITS > 0
            END

            PRINT 'BALANCE UNIT =' + CONVERT(VARCHAR(50), @TSD_BALANCEUNITS) + ' ==> ' + 'CERT IN UNITS =' + CONVERT(VARCHAR(50), @TSD_UNITSINCERT);

            FETCH NEXT
            FROM LOCK_CERT_UNITS
            INTO @TSD_BALANCEUNITS
                ,@TSD_UNITSINCERT
        END

        CLOSE LOCK_CERT_UNITS

        DEALLOCATE LOCK_CERT_UNITS
        GO

Answer 1

This command:

UPDATE IS_TRX_TRX_PROCESSED
SET    TSD_UNITSINCERT = TSD_BALANCEUNITS
WHERE  (TSD_ACCCODE = 8775)
AND    TSD_BALANCEUNITS > 0

update all records where TSD_ACCCODE = 8775 and TSD_BALANCEUNITS > 0, it doesn't matter if its sum 999, you need to identify in some way wich records must be updated.

Second, according the result, this never happens. That means that IF (SUM(@CHECKFLAG) <= 199.00) is never true. I suppose because you never initializes it value to 0.

SET @CHECKFLAG = 0;